<p>The increasing adoption of 6U–8U CubeSat platforms for Earth observation, communication, and scientific missions has created a growing demand for compact, high-performance attitude control actuators capable of supporting agile mission profiles under strict volume and mass constraints. This paper presents a mission-driven, system-level design and sizing methodology for an in-house reaction wheel pyramid assembly fully constrained within a standard 1U (10 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\times $</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> 10 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\times $</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> 10 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\hbox {cm}^{3}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mtext>cm</mtext> <mn>3</mn> </msup> </math></EquationSource> </InlineEquation>) volume and scalable across 6U, 6U-XL, and 8U CubeSat platforms. The proposed methodology starts from time-constrained agile mission requirements representative of single-pass multi-strip imaging scenarios and systematically propagates these requirements to spacecraft inertia modeling, reaction wheel torque, and angular momentum sizing. A conservative worst-case approach based on a required slew rate of 5 deg/s yields angular momentum requirements ranging from 0.0113 to 0.0204 N<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\cdot $</EquationSource> <EquationSource Format="MATHML"><math> <mo>·</mo> </math></EquationSource> </InlineEquation>m<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$\cdot $</EquationSource> <EquationSource Format="MATHML"><math> <mo>·</mo> </math></EquationSource> </InlineEquation>s across the considered platforms. A four-wheel pyramidal configuration with a cant angle of <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$35.26^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>35</mn> <mo>.</mo> <msup> <mn>26</mn> <mo>∘</mo> </msup> </mrow> </math></EquationSource> </InlineEquation> is adopted to provide full three-axis control authority with single-wheel failure tolerance. To satisfy the derived momentum requirements within the 1U volume constraint, high-density tungsten flywheels are selected, enabling compact geometries with radii of 20 mm and thicknesses between 5.75 and 10.32 mm. Torque analysis results in minimum single-wheel torque demands between 6.14 and 11.03 mN<InlineEquation ID="IEq7"> <EquationSource Format="TEX">$\cdot $</EquationSource> <EquationSource Format="MATHML"><math> <mo>·</mo> </math></EquationSource> </InlineEquation>m, while a motor trade study demonstrates continuous torque margins exceeding <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$2\times $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>2</mn> <mo>×</mo> </mrow> </math></EquationSource> </InlineEquation> in the worst-case 8U scenario using commercially available brushless DC motors. CAD-based geometric verification confirms the feasibility of integrating the complete four-wheel assembly within a centralized 1U volume, with an estimated total mass of approximately 1.96 kg, corresponding to about 14% of an 8U spacecraft. The presented architecture demonstrates the feasibility of integrating a compact fault-tolerant four-wheel reaction wheel pyramid within a centralized 1U volume while maintaining scalability across 6U–8U CubeSat platforms. The proposed design establishes a practical and scalable foundation for compact, fault-tolerant attitude control architectures suitable for agile CubeSat missions and future flight-qualified ADCS implementations.</p>

Mission-driven system-level design and sizing of a 1U-constrained reaction wheel pyramid for 6U–8U CubeSats

期刊论文
发表日期：

2026年7月30日

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Xixi Zhang,
Ghadi M AL-Amer,
Teef A ALHarthi,
Yaqin Saada,
Shouq J ALAbdullah,
Fadil M Younes,
Atif Mahmood,
Ayman M Abadallah

摘要

The increasing adoption of 6U–8U CubeSat platforms for Earth observation, communication, and scientific missions has created a growing demand for compact, high-performance attitude control actuators capable of supporting agile mission profiles under strict volume and mass constraints. This paper presents a mission-driven, system-level design and sizing methodology for an in-house reaction wheel pyramid assembly fully constrained within a standard 1U (10 $\times $ $\times$ 10 $\times $ $\times$ 10 $\hbox {cm}^{3}$ ${cm}^{3}$ ) volume and scalable across 6U, 6U-XL, and 8U CubeSat platforms. The proposed methodology starts from time-constrained agile mission requirements representative of single-pass multi-strip imaging scenarios and systematically propagates these requirements to spacecraft inertia modeling, reaction wheel torque, and angular momentum sizing. A conservative worst-case approach based on a required slew rate of 5 deg/s yields angular momentum requirements ranging from 0.0113 to 0.0204 N $\cdot $ $\cdot$ m $\cdot $ $\cdot$ s across the considered platforms. A four-wheel pyramidal configuration with a cant angle of $35.26^\circ $ $35 . 26^{\circ}$ is adopted to provide full three-axis control authority with single-wheel failure tolerance. To satisfy the derived momentum requirements within the 1U volume constraint, high-density tungsten flywheels are selected, enabling compact geometries with radii of 20 mm and thicknesses between 5.75 and 10.32 mm. Torque analysis results in minimum single-wheel torque demands between 6.14 and 11.03 mN $\cdot $ $\cdot$ m, while a motor trade study demonstrates continuous torque margins exceeding $2\times $ $2 \times$ in the worst-case 8U scenario using commercially available brushless DC motors. CAD-based geometric verification confirms the feasibility of integrating the complete four-wheel assembly within a centralized 1U volume, with an estimated total mass of approximately 1.96 kg, corresponding to about 14% of an 8U spacecraft. The presented architecture demonstrates the feasibility of integrating a compact fault-tolerant four-wheel reaction wheel pyramid within a centralized 1U volume while maintaining scalability across 6U–8U CubeSat platforms. The proposed design establishes a practical and scalable foundation for compact, fault-tolerant attitude control architectures suitable for agile CubeSat missions and future flight-qualified ADCS implementations.